Allen & Overy (A&O) has hired David Herlihy from Skadden Arps Slate Meagher & Flom in a move that hands it a major figure in the field of investor-state dispute settlement (ISDS) and public international law, both blue riband elements of a full-service arbitration practice.

Herlihy is leaving Skadden after twenty years – nine as a partner – and will initially be based at A&O's Shoreditch headquarters before dividing his time between London and Dublin, subject to regulatory approvals.

His arrival will significantly bolster A&O’s international arbitration offering. Alongside his ISDS practice, he will bring strong sectoral experience to his new firm, especially in the fields of energy, telecoms and technology, all key areas of focus for A&O.

Linked to his commercial arbitration and ISDS practice, Herlihy also handles high-stakes competition and international tax disputes, which also dovetails with A&O’s wider practice. 

Key work includes representing Vodafone in a long-running $5.5bn tax dispute with India and Next Era in its Energy Charter Treaty challenge to Spain, which resulted in a €300m arbitration award. He also represented Cyprus in defending €1bn worth of ISDS claims arising out of the global financial crisis and regularly advises South Sudan in investor-state matters. 

While drawing less attention than his ISDS work, Herlihy has acted in significant LCIA, ICC, and UNCITRAL cases as well as associated enforcement actions and satellite litigation, including in offshore cases such as the 2005 BVI defence of Sibir Energy’s £1bn claim against Skadden’s former client Roman Abramovich, Sibneft and others. 

As a treble-qualified lawyer in London, Dublin, and New York, Herlihy has represented clients in the UK, the EU, India, and Africa, and in Spanish-language disputes in Europe and Latin America.

Most closely associated with ICC arbitration, Herlihy has served on ICC task forces on investor-state arbitration. At Skadden, he acted as the firm's London graduate recruitment partner and was a member of the firm's London diversity committee, as well as its European LGBTQ Affinity Network. 

Herlihy’s appointment at A&O compensates for the 2021 departure of Matthew Gearing QC, the firm’s former co-head of international arbitration, who joined Fountain Court Chambers as an arbitrator and advocate. The move will see him link up with Gearing’s successor, Mark Levy QC, as well as 2022 silk, Kate Davies McGill QC, and younger partners such as James Freeman and Suzanne Spears. 

It is the latest in a series of lateral hires aimed at expanding the global reach of the firm's arbitration department. In Washington DC, it hired Jenner & Block’s highly rated co-head of arbitration, Patrick Pearsall, in 2020, and Arnold & Porter’s Gaela Gehring Flores a year later. In 2021 it made up arbitration partners in Hong Kong and Slovakia. 

Market sources, however, said Herlihy represented the most significant arbitral arrival to A&O’s equity so far, which would boost both the firm’s growing Americas practice as well as the London partner group.

Levy said: “David’s hire demonstrates our commitment to investing in our international arbitration practice, so that we can continue to support our clients in resolving their most complex disputes. I look forward to working closely with him going forward.”

The firm’s global head of disputes, Karen Seward, added, “David is a highly successful and well-respected international arbitration lawyer, who has built a pre-eminent practice”, highlighting his sectoral and regional expertise in particular, alongside that of other recent hires such as those of Norton Rose Fulbright’s Michael Godden and RPC’s Andy McGregor, among others.

She added: “David’s focus on collaboration, as well as his keen interest in advocating for diversity and inclusion, align perfectly with our values and priorities.” 

David Kavanagh QC, Skadden’s head of international arbitration, wished his colleague well, saying: “We're sorry to see him go but understand his wish to relocate to Dublin with Allen & Overy for family reasons."